Railway track circuits



Dec. 25, 1934. B s v c 1,985,577

RAILWAY TRACK CIRCUITS Filed May 27, 1932 1NV1:SNTOR. Ben amin Mslzeleuwlz.

BY 6222M HIS ATTORNEY.

Patented Dec. 25, 1934 warren STATES PATENT ()FFIQ Application May 27, 1932, Serial No. 613,953

6 Claims.

My invention relates to railway track circuits, and has for an object the provision of means for reducing the time required for the release of the track relay armature when a train enters the associated section.

I will describe one form of track circuit embodying my invention, and will then point out the novel features thereoi in claims.

The accompanying drawing is a diagrammatic view showing one form of track circuit embodying my invention.

Referring to the drawing, the reference characters 1 and l designate the track rails of a stretch of railway track, which track rails are divided by means of insulated joints 2 to form a track section A-B. A track battery 3 is connected with the rails of section A-B adjacent one end of the section, preferably in series with the usual track resistor 4, and located adjacent the other end of the section is a track relay R.

The track relay R, in the form here shown, comprises an electromagnet consisting of the usual magnetizable cores 5 connected by a backstrap 6 and provided with pole pieces '7. Only one core and one pole piece are shown in the drawing because the remaining core and pole piece are directly behind the one illustrated. The cores 5 are provided with the usual operating winding 8 which is connected with the rails 1 and 1 The cores 5 are also provided with an auxiliary winding 9 which is connected across the winding 8 in series with a condenser 10. The winding 8 may have any suitable resistance, but the winding 9 will preferably have a very low resistance. The relay also comprises the usual tractive armature 11, pivotally mounted at 11 for swinging movement toward and away from the pole pieces 7, and biased by gravity to an open position. Secured to the underside of the armature 11 by means of insulating studs 12 is a contact finger 13 which, when the armature 11 is picked up, engages a fixed front contact member 14 to close a contact 13-44.

The operationvof the track circuit is as follows: When section A-B is unoccupied, winding 8 is energized and condenser 10 is charged to the potential which appears across winding 8, but winding 9 is deenergized. Under this condition, armature 11 is picked up, so that contact 13-14 is closed. When a train enters section A-B, however, the wheels and axles will form a low resistance shunt across winding 8, and this winding will therefore become substantially deenergized, so that the flux which was previously set up in the cores 5 and armature 11 by the current from the battery 3 flowing in this winding will start to decay. Simultaneously, the wheels and axles will also form a low resistance shunt across the auxiliary winding 9 and the condenser 10 in series which will cause the condenser 10 to discharge through the closed circuit formed by the condenser 10, the winding 9, and the winding 8 in series, and also through the circuit formed by the condenser 10, the winding 9, and the train shunt in series. It will be readily understood from an inspection of the drawing that any current from the condenser 10 which flows in the winding 8 will flow through this winding in the same direction as the current from the battery 3, and thus tend to delay the decay of the flux in the cores 5 and the armature 11, but the resistance of the closed circuit including the winding 8 will be so high compared to that of the circuit including the train shunt, that the magnitude of the current flowing in the winding 8 under these conditions will be so small as to be almost negligible. The winding 9 is so disposed on the cores 5 that the current from the discharging condenser flowing in this winding will set up a flux in the cores 5 and the armature 11 in opposition to the flux which was previously set up in these members by the current from the battery 3, and it follows that this latter flux will accelerate the decay of the flux in the cores 5 and the armature 11, with the result that the armature 11 will release and open the contact 13-14 much more quickly than would be the case if the winding 9 and the condenser 10 were not provided.

When the train departs from the section I l-B, current will again start to how in winding 8 which will attract the armature 11 thus closing the contact 13-14. Current will also flow in winding 9 until condenser 10 becomes charged, and since the direction of flow of this current will be opposite from that due to the discharging con-- denser, it follows that the resultant flux will aid in the picking up of the armature 11.

Altheugh 1 have herein shown and described only one form of railway track circuit embody-- ing my invention, it is understood that various changes and modifications may he made therein within the scope of the appended claims without departing from the spirit and scope of my inventicn.

Having thus described my invention, what I of said sectic .1 and the other or which is connecte i across said one winding in series with a condenser.

2. In combination, a section of railway track, a source of direct current connected with the rails of said section adjacent one end of the section, and a track relay having two windings one of which is connected with the rails of said section adjacent the opposite end of said section from said source and the other of which is connected across said one winding in series with a condenser in such manner that the current which flows in said other winding when said condenser becomes discharged due to a train shunting the rails of said section will set up a flux in said relay in opposition to the flux which is set up in said relay by current from said battery flowing in said one winding.

3. In combination, a section of railway track, a source of direct current connected with the rails of said section adjacent one end of the secion, a relay having an armature biased by gravity to an open position and a main winding for closing said armature connected with the rails of said section adjacent the opposite end of said section from said source, said relay also having means for expediting the release of aid armature comprising an auxiliary winding of relatively low resistance connected across said main Winding in series with a condenser in such manner that the current which flows in said auxiliary winding when said condenser becomes charged will ore ate in said armature a flux which aids the closing of said armature but that the current which flows in said auxiliary winding when said condenser becomes discharged will create in said armature a fiux which opposes the flux created thereby by current from said source flowing in said main winding.

4 In combination, a section of railway track, a source of current connected with the rails of said section, a direct current track relay having an operating winding and an auxiliary winding both receiving energy from the rails of said section, and a condenser in the circuit of said auxiliary winding, said two windings being connected in such direction that the charging current flowing into said condenser through said auxiliary winding aids the current in said operating winding, whereby when said track becomes shunted the discharge current flowing through said auriiliary winding out of said condenser will oppose the effect of the current in said operating winding to expedite the release of said track relay.

5. In combination, a section of railway track, a track relay having an operating winding and an auxiliary winding, means for supplying unidirectional current from said rails to said two windings, and a condenser in the circuit of said auxiliary winding, said two windings being connected in such direction that the charging current flow ing into said condenser through said auxiliary winding aids the current in said operating winding, whereby when said track becomes shunted the discharge current flowing through said auxiliary winding out of said condenser will oppose the effect of the current in said operating winding to expedite the release of said track relay.

6. In combination, a section of railway track, a track relay having an operating winding, means for supplying unidirectional current from said rails to said operating winding, an auxiliary winding for said track relay energized from the po tential drop across said operating winding, and a condenser in the circuit of said auxiliary winding, said two windings being connected in such direction that the charging current flowing into said condenser through said auxiliary winding aids the cLu-rent in said operating winding, whereby when said track becomes shunted the discharge current flowing through said auxiliary winding out of said condenser will oppose the effect of the current in said operating winding to expedite the release of said track relay.

BENJAMIN MISHELEVICH. 

